Coating paper



o as color."

Patented Juno: 19:42-

uNlr-so STATES PATENT "mm orrlcs cos'rmc urns James Grant Hayden, In, Westemnort, mislsignor to West Virginia Pulp and Paper Compm, New York, N. Y., a corporation of Delaware NoDrawing. Application May 11, 19:9,

Serial No. 272.861

Claims.

' My present invention relates to improved compositions for coating paper and to the paper coated therewith.-

Ordinarily, paper is coated with a composi-' In lieu of a suspension of mineral pigments in water and a water soluble adhesive, the present invention seeks to provide a coating composition comprising a suspension of mineral pigments in a volatile, non-aqueous, preferably non-inflammable solvent together with an adhesive of special properties soluble therein. when using a non-aqueous solvent the base sheet to be coated not wet in the usual sense, whereby it does not lose its strength nor does it stretch or wrinkle or lose its shape. Furthermore, the paper so coated, depending upon the amount of adhesive used, is to a considerable degree wash or waterproof.

After considerable experimentation I have dis covered that various synthetic resins or plastic materials may be used as the adhesive with volatile non-aqueous and non-inflammable solvents in which the resins do not exceed 30% of the total coating composition on a dry basis. Among plastic materials which have been found satisfactory may be mentioned ethyl cellulose, polyvinyl acetate-methylal, polyvinyl acetate-acetal, polystyrene, cellulose acetobutyrate.

Solvents which have been found satisfactory are volatile chlorinated hydrocarbon compounds such, for example, as carbon tetrachloride, ethylene dichloride, dichlor ethylene, trichlor ethylene, chloroform, etc., it being desirable that the boiling point of the solvents selected should not be in excess of 200 C.

The following common mineral pigments may (2) Solvent: carbon tetrachloride Adhesive: polystyrene Pigment: clay Percent adhesive: 15 Percent solids: 5.5

Solvent: dichlor ethylene Adhesive: polyvinyl acetate-methylai Pigment: clay Percent adhesive: 15

Percent solids:- 8

Solvent: dichlor ethylene Adhesive: polyvinyl acetate-acetal Pigment: clay Percent adhesive; 15

Percent solids: 8.5

Solvent: dichlor ethylene Adhesive: polyvinyl acetate-acetal Pigment: clay Percent adhesive: 5

Percent solids: 8.5

Solvent: dichlor ethylene Adhesive polyvinyl ac'etate-methylal Pigment: clay Percent adhesive: 5

Percent solids: 7.5

Solvent: dichlor ethylene Adhesive: cellulose acetobutyrate Pigment: clay Percent adhesive: 15' Percent'solids: 8.5.

Solvent: ethylene dichloride Adhesive: polyvinyl acetate-acetal Pigment: chalk Percent adhesive: 10.0

Percent, solids: 11.9v

(9) Solventwethylene dichloride Adhesive: polyvinyl acetate-a'cetal" Pigment: calcium sulflte Percent adhesive: 10, Percent solids: 11.3

Solvent: ethylene dichloride Adhesive: ethyl cellulose Pigment: calcium sulflte Percent adhesive: 15 0 Percent solids: 9.0;

It will be noted that in the foregoing exampies the amount of adhesive is varied from 3% to as high as15%, although for special purposes, as where a high degree of water resistance is required, theamount of adhesive may run as high as 30% When using appreciably less adhesive than 3% the coating may have a tendency torubofl; Y a v The adhesives mentioned in theforegoing are examples of a classkwhichare readily compatible with the ordinary pigments, Other non-watersoluble adhesives may be found to exhibit a cer- (11) 100 g. of clay 15 g. of methyl methacrylate resin 6 g. of sulfonated castor oil 225 g. of ethylene dichloride 35% solids 100 g, oiclay 15 g.,oi methyl methacrylate resin 6 g. of dibutyl phthalate 225 g. of ethylene dichloride 35% solids 100 g. of clay 15 g. of polyvinyl acetate 6 g. of sull'onated castor oil 225 g. of ethylene dichloride 35% solids 100 g. of clay 15 g. of polyvinyl acetate 6 g. of dibutyl phthalate 225 g. of ethylene dichloride 35% solids 100 g. of clay 15 g. of acrylic acid resin 6 g. of dibutyl phthalate 225 g. oi ethylene dichloride 35% solids In making up the coating compositions according to the above formulas, the pigment is ground with the adhesive, the plasticizer, it any, and suillcient solvent to give a working consistency, a suitable mill, e. g., an ink grinder, being employed for the purpose. The ground mixture is then diluted with the proper amount of solvent.

The composition according to the foregoing examples may be applied to the web to be coated in known manner with recovery of the solvent which is volatilized during the drying operation.

The web to be coated may be any paper of known composition and properties such as are commonly used in the art of making coated papers Further advantages of the improved composition are as follows:

cutting" down the amount of so called broken. I

Various changes will occur to those skilled in the art which do not depart from the spirit of my invention. 4

I claim:

1. An improved paper having a base sheet and a coating comprising clay and in which the clay particles, are held together and to the base sheet by a synthetic water-insoluble plastic material of the group consisting of Ethyl cellulose (carbon tetrachloride soluble) Polyvinyl acetate-methylal Polyvinyl acetate-acetal Polystyrene Cellulose acetobutyrate Methyl methacrylate resin Polyvinyl acetate Acrylic acid resin the said coating having been deposited on the base sheet from a solution or the plastic material in a volatile organic solvent carrying the clay in suspension and the content of said plastic ma-' terial being from 3% to based on the dry weight of the coating.

2. An improved paper having a base sheet and a coating of mineral pigments, characterized by the particles of said coating being held together and to the base sheet by synthetic plastic material of the group consisting of methyl methacrylate resin, polyvinyl acetate, acrylic acid resin, not normally wetting the coating pigment particles, said plastic material being admixed with a plasticizer,- the said coating having been deposited on the base sheet from a solution of the plastic material in a volatile organic solvent carrying the mineral pigments in suspension and the content of said plastic material being from 3% to 30% based on the dry weight oi coating.

3. An improved paper having a base sheet and a coating comprising mineral pigments normally used in the manufacture of coated papers, and in which the pigment particles-are held together and to the base sheet by ethyl cellulose which is soluble in a chlorinated volatilev solvent, the said coating having been depositedon the base sheet from a solution of the ethyl cellulose in the said solvent carrying the pigments in suspension and the content of said ethyl cellulose being from 1. The use of a small amount of'the adhesive makes it possible to have a sheet with high color and brightness without having to use special pigments and dyes. 4

2. Solvent coated papers are stronger than those with aqueous coatings.

3. There is no tendency for the paper to blacken when calendered.

4. There is no distortion of the paper while being coated.

5. There is no tendency spots to develop.

for foam or grease 6. There is no deterioration of the adhesive during storage or during the makeup period in the color room whereaiter it is placed on the paper. It also makes a sheet having no offensive odor. Q

7. Since there is no distortion of during coating, the formation oi wrinkles and calender cuts is substantially eliminated. thus "the sheet 3% to 30% based on the dry weight of the coating 4. An improved paper having a base sheet and a coating or mineral pigments and in which the pigment particles are held together and to the base sheet by polystyrene, the said coating having been deposited on the base sheet from a solution of the polystyrene in a volatile organic sol- Vent carrying the mineral pigments in suspension and the content or said polystyrene being from 3% to 30% based on the dry weight or the coating. 1

5. An improved paper having a base sheet and a coating of mineral pigments and in which the pigment particles are.held together and to the base sheet by methyl methacrylate resin, the said coating having been deposited on thebase sheet from a solution of the methyl methacrylate resin JAMES GRANT HAYDEN, Jl. 

